Secondary recovery shell



J. W. GLASS SECONDARY RECOVERY SHELL Filed May 27, 1964 ril ""iln March 22, 1966 a AAA? INVENTOR. James 14/ Glass.

ATTORNEY.

United States Patent .3,241,488 SECONDARY RECOVERY SHELL James W. Glass, New Castle, Pa., assignor to Glass, Scott & Wilcox, Inc., New Castle, Pa., a corporation of Pennsylvania Filed May 27, 1964, Ser. No. 370,448 3 Claims. or. 102-24) This invention relates to a shell such as used in shooting an oil well and more particularly to a shell incorporating a novel arrangement of shaped explosive charges relying on the Munroe effect to generate highly penetrative jets, such as useful in breaking the oil sand formation in an oil well so as to permit recovery of additional oil therefrom.

The principal object of the invention is the provision of a secondary recovery shell incorporating a novel focused arrangement of vertically spaced, shaped charges.

A further object of the invention is the provision of a secondary recovery shell which may be easily and economically formed and used in a more or less customary manner for treating oil wells so as to increase the productive flow therefrom.

A still further object of the invention is the provision of a secondary recovery shell in which the shaped explosive charges therein are so arranged that they focus upon a common force center corresponding with a desired side location of the secondary shell itself.

Those skilled in the art will recognize that new oil wells require preparation and shooting of a casing in order to go into production and older oil wells can be desirably treated by repeating the shooting operation so as to permit a secondary recovery from the oil-bearing strata in the earth. Such shaped charges as have heretofore been used in shooting oil wells have been primarily arranged for a series of vertically spaced, individually acting perforating actions such as, for example, that disclosed in US. Patent 2,974,589. Still other uses of shaped charges have been proposed for obtaining samples of the wall strata of an oil well or other bore and wherein a multiplicity of small shaped charges are arranged circumferentially and focused on a point well to one side of the casing in which they are mounted so that their resulting effect is to break away a portion of the material through which the bore extends. The material may then be recovered and examined for sampling or other purposes.

The present invention differs from these proposals and constructions in that it provides a shell suitable for shoot ing producing oil wells so as to effect a so-called secondary recovery action which in effect comprises increasing the fiow of oil into the well. In order to accomplish this purpose, it is essential that the explosive charge, and particularly the shaped charge used, be very highly intensified relative to anything heretofore known in the art or practiced, and the present invention relates to a secondary recovery shell having such characteristics that enable it to successfully penetrate the oil-bearing strata, or sand, as it is sometimes termed in the art, sufiiciently to substantially increase the flow of oil into the well. This is accomplished by a novel and unique arrangement of the shaped charges themselves so that their concentrated explosive jet actions are themselves focused upon a desirable point and the sum total effect of the explosive charges is thereby multiplied many times.

With the foregoing and other objects in view which will appear as the despecription proceeds, the invention resides in the combination and arrangement of parts and in the details of construction hereinafter described and claimed, it being the intention to cover all changes and modifications of the example of the invention herein chosen for purposes of the disclosure, which do not constitute departures from the spirit and scope of the invention.

The invention is illustrated in the accompanying drawing, wherein:

FIGURE 1 is a vertical section through a portion of an oil well casing showing the secondary recovery shell therein with broken lines indicating the directions of the force lines of the shaped charges.

FIGURE 2 is a horizontal section on line 22 of FIGURE 1 with broken lines again indicating the direction of the focused shaped charges therein.

FIGURE 3 is an enlarged horizontal section on line 3-3 of FIGURE 1 with broken lines indicating the direction of force of the shaped charge.

By referring to the drawings and FIGURE 1 in particular, it will be seen that an oil well casing, or a portion thereof, has been indicated by the numeral 10 and that a secondary recovery shell which comprises a cylindrical casing 11 has been lowered therein to a desired position. The secondary recovery shell includes a top portion 12 and a bottom 13 and contains three shaped charges which comprise conical body members which are hollow and which are essentially sections of explosive material 14, 14. These conical sections of explosive material 14, 14 are encased in conical body members 15, 15 which may be any desired material sufficiently to hold the explosive material 14 as during the forming or shaping thereof, and the three shaped charges are positioned in vertical position relative to one another with the centralmost charge having its axial center line on a horizontal line transversely of the secondary recovery shell casing 11 and preferably midway between the ends 12 and 13 thereof.

The upper and lower explosive charges are arranged within the cylindrical secondary recovery shell casing 11 so that their axial center lines or lines of force, such as are indicated by the broken lines and arrows in FIG- URE 1 of the drawing, are at an acute angle to the axial center line of the centermost shaped charge and so that the extensions of the lines of force converge at a point of the side of the secondary recovery shell and directly to one side of the center shaped charge as above described.

The shaped charges are positioned within the secondary recovery shell casing 11 by any suitable means, such as a foamed plastic, for example, and generally indicated by the numeral 16, and are thereby held in the desired and highly important focused position as seen in FIGURE 1 of the drawings.

In FIGURE 2 of the drawings, the cross sectional elevation shows the upper outer surface of the center shaped charge and its housing 15 and portions of the inner conical surface of the lower shaped charge and its housing 15.

Shaped explosive charges relying on the Munroe effect to generate highly penetrative jets are well known. Such shaped charges may in general comprise a cylinder of explosive material, one end of which is hollowed out and lined with a thin metallic liner. The charge is detonated at the other end and the explosive wave traveling in the explosive material causes the liner to collapse and form the penetrating jet from the hollowed end. The explosive material is detonated by suitable means known in the art, such as electrical firing caps and/ or consumable fuses as desired, and it will occur to those skilled in the art that the size and, therefore, the effect of the shaped charges is necessarily limited by the diameter of the housing of the shell in which they are positioned, and this, in turn, is limited by the diameter of the casing in the oil well to be treated.

In order to increase the efficiency of the explosive charge, the present invention locates the plurality of vertically spaced, shaped charges and arranges them so that the center one is focused directly sidewardly while the upper and lower charges are in turn focustd at acute angles to the horizontal focus line of the centrally located charge. In FIGURE 1 these focus lines are indicated by the letters A, B and C, and it will be observed that they meet at one side of the cylindrical casing 11 of the secondary recovery shell.

By referring now to FIGURE 3 of the drawings, a cross sectional enlargement of one of the explosive shaped charges seen in FIGURES 1 and 2 of the drawings may be seen, and it will be observed that directional arrows have been applied to indicate the lines of force generated by the explosive material. The principal directional focused line of force is again indicated by the letter A. This is, in turn, formed by the converging lines of force A which come from the inner sides of the conical shaped charge. The lines of force that are created by the detonation of the explosive 14 will thus be seen to be highly concentrated in the area within the conical shape of the device and only minimal force lines extend in other directions. The material in the secondary recovery shell casing 11 which supports and positions the shaped charges 14, 14 adequately distributes this force so that it is in effect spread over the entire inner surface of the secondary recovery shell casing opposite to that point therein which comprises the focusing point of the shaped charges as heretofore explained.

It will thus be seen that a secondary recovery shell incorporating shaped explosive charges arranged in a novel focused pattern has been disclosed which shaped recovery shell meets the several objects of the invention, and having thus described my invention, what I claim is:

1. A shaped explosive charged device comprising a cylindrical container, three uniform sized shaped explosive charges positioned within said container and means in said container for supporting said shaped explosive charges, said shaped explosive charges comprising hollow conical members having inner and outer walls uniformly spaced and arranged in longitudinally spaced relation to one another on the axial center line of said container, each of said shaped explosive charges being of a size from the base to the apex substantially exceeding onehalf the diameter of the cylindrical container, the center one of said shaped explosive charges positioned with its axis transversely of the axis of said container and wherein the shaped explosive charges on either side of said center explosive charge are positioned at acute angles thereto with their extended axial center lines lying on acute angles closely spaced with respect to the base of said center one of said conical explosive charges and converging with the extended axial center line of the center explosive charge and meeting with said center line at a point within said container.

2. The shaped explosive charge device as set forth in claim 1 and wherein said explosive charges on either side of the center explosive charge are positioned with their axial center lines approximately 55 from horizontal and spaced with respect to said center shaped explosive charge so that said axial center lines converge in a side wall of said container.

3. The shaped explosive charge device set forth in claim 1 and wherein the axis of the symmetrical container is positioned vertically, and the shaped explosive charges are positioned therein in vertically spaced relation to one another.

References Cited by the Examiner UNITED STATES PATENTS 2,587,243 2/1952 Sweetman 102-24 2,616,370 11/1952 Foster 2.. 102-24 2,757,611 8/1956 Church et al 102-20 2,984,307 5/1961 Barnes 102-24 3,089,416 5/1963 Gilbert 102-20 BENJAMIN A. BORCHELT, Primary Examiner. 

1. A SHAPED EXPLOSIVE CHARGED DEVICE COMPRISING A CYLINDRICAL CONTAINER, THREE UNIFORM SIZED SHAPED EXPLOSIVE CHARGES POSITIONED WITHIN SAID CONTAINER AND MEANS IN SAID CONTAINER FOR SUPPORTING SAID SHAPED EXPLOSIVE CHARGES, SAID SHAPED EXPLOSIVE CHARGES COMPRISING HOLLOW CONICAL MEMBERS HAVING INNER AND OUTER WALLS UNIFORMLY SPACED AND ARRANGED IN LONGITUDINALLY SPACED RELATION TO ONE ANOTHER ON THE AXIAL CENTER LINE OF SAID CONTAINER, EACH OF SAID SHAPED EXPLOSIVE CHARGES BEING OF A SIZE FROM THE BASE OF THE APEX SUBSTANTIALLY EXCEEDING ONEHALF THE DIAMETER OF THE CYLINDRICAL CONTAINER, THE CENTER ONE OF SAID SHAPED EXPLOSIVE CHARGES POSITIONED WITH ITS AXIS TRANSVERSELY OF THE AXIS OF SAID CONTAINER AND WHEREIN THE SHAPED EXPLOSIVE CHARGES ON EITHER SIDE OF SAID CENTER EXPLOSIVE CHARGE ARE POSITIONED AT ACUTE ANGLES THERETO WITH THEIR EXTENDED AXIAL CENTER LINES LYING ON ACUTE ANGLES CLOSELY SPACED WITH RESPECT TO THE BASE OF SAID CENTER ONE OF SAID CONICAL EXPLOSIVE CHARGES AND CONVERGING WITH THE EXTENDED AXIAL CENTER LINE OF THE CENTER EXPLOSIVE CHARGE AND MEETING WITH SAID CENTER LINE AT A POINT WITHIN SAID CONTAINER. 